Pancreatic cancer is the fourth leading cause of cancer related death in the United States. There is an urgent need to identify novel biomarkers for early diagnosis and targets for therapeutic interventions. Overexpression of EGFR in PC cells plays a crucial role in the uncontrolled proliferation of neoplastic cells. Amplification or overexpression of the wild-type EGFR (EGFRwt) gene is frequently associated with rearrangements or alternate splicing resulting in the expression of structurally altered EGFR mRNA and protein. EGFRvIII is the most is the most common naturally occurring mutant form of EGFR and is expressed in many cancer types including glioblastoma, breast, ovarian, head and neck, lung and prostate cancer. Although amplification of EGFR and its ligands is well documented in pancreatic cancer, no efforts have been made to study the incidence or involvement of EGFRvIII in pancreatic cancer. Our preliminary results suggest that EGFRvIII is highly expressed in pancreatic cancer tissues. Based on the preliminary findings we hypothesize that "naturally occurring epidermal growth factor receptor variant III (EGFRvIII) contributes to the pathogenesis of pancreatic adenocarcinomas". To test the hypothesis following specific aims are proposed: SPECIFIC AIM I will investigate the expression of EGFR and EGFR variants in human pancreatic tumors by reverse transcriptase- polymerase chain reaction (RT-PCR) and immunohistochemical analysis. PCR- amplification will demonstrate the expression of mRNA. Immunohistochemical analysis using a EGFRvIII specific monoclonal antibody will indicate the presence and cellular localization of the EGFRvIII protein. This aim will provide the information on the incidence of expression of EGFRvIII in human pancreatic tumors. SPECIFIC AIM II will express EGFRvIII in highly tumorigenic (HPAF) and poorly tumorigenic (MiaPaCa) human pancreatic cancer cell lines and immortalized human pancreatic ductal cells (HTERT/HPNE) to establish its contribution to the malignant phenotype. This aim will support our prediction that expression of EGFRvIII in cultured immortal pancreatic cells is sufficient to lead to a transformed phenotype;that the cells will gain the ability to form foci in soft agar and to form tumors in nude mice. Taken together, these studies will provide the incidence and function of a novel naturally occurring variant of EGFRvIII in the lethal pancreatic cancer. The long-term goal of this project is to use the newly developed anti-EGFRvIII antibodies for targeted therapy of pancreatic cancer. PUBLIC HEALTH RELEVANCE: Mutant epidermal growth factor receptor, EGFRvIII is an attractive target for targeted therapy due to its tumor-restricted expression and presence of unique antigenic epitopes. In this grant application, we propose to investigate EGFRvIII's expression in pancreatic tumors (various grades of malignancy), its oncogenic function in immortal pancreatic cells, and its effect on tumorigenecity of pancreatic cancer cells.